A FreshOTG portable vacuum set includes the upper and lower parts of the valve that work together. They need to be attached to the bags to create a vacuum point for the easy manual pump to pump out air using your hands, unlike machines that take up a lot of counter space. The upper part is made from food grade silicone, and the lower part contains a small sharp point (made from food grade polypropylene) that is designed to break the bag and create a vacuum point.
The FreshOTG valve is made from food grade silicone, a synthetic polymer created by adding carbon and/or oxygen to silicone. It can exist as a solid, liquid or gel and is often used in medical devices like pacemakers, joint replacements and implants. It is generally considered safe for these uses. It is also often used to make silicone bakeware. Silicone is also dishwasher safe, petroleum free and should not fade or scratch. FreshOTG valves are 100% safe to use at low temperatures and in the refrigerator or freezer, but they are not designed for baking or high temperature use.